Control apparatus



Nov. 26, 1946. H. F. ELLIOTT CONTROL APPARATUS Filed Dec. 16, 1945 I 4Sheets-Sheet 1 INVENTOR. Hamid 171 7 16017? Nov. 26, 1946. H. F. ELLIOTT2,411,619

CONTROL APPARATUS a? 215 Q 41a 420.

745% 28b fall I, v $4 Z9 Z915 5 44b INVENTOR. I

Nov. 26, 1946. H. F. ELLIOTT CONTROL APPARATUS Filed Dec.

16, 1945 4 Sheets-Sheet 3 1 'INVENTOR.

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Nov. 26, 1946. H, F, ELLIOTT I 2,411,619

C ON TROL APPARATUS Filed Dec. 16, 1943 4 Sheets-Sheet 4 T0 CATHODE HEATEES INVENTOR.

.sv Mpgm v 0g acting lost-motion and also "for -p have been movedintoPatented Nov. 26,1946

UNITED STATE I ooN'raoL APFARATUS v Harold fF'. Elliott, Belmont, Mass.

Application The present invention relates to improvements .incontrolmechanisms and more particularly to improved control apparatusfor automatically andao'curately tuning a radio receiving system to anydesired one of a plurality of signal channel-: I Itis an object of thepresent invention to provideautomatic' tuning apparatus for a radioreceiven'which' is extremelyaccurate and positive inits operation tomove the frequency changing means to any setting corresponding to adesired station, compact in arrangement, and is of simple andinexpensive construction.

Itii another object 'of the invention to'provide control'apparatusof thecharacter described, wherein a control xunit of improved ruggedconstruction is provided for 'moving' the settable element of thefrequency changing means into each pr'e'de'termined:sett'in'gv and forlocking the element' in the established setting, while at the same timepermitting the settable elementito be'moved in" .either direction away:from the established setting when. actuated through a second controlunit corresponding to adiiierent predetermined setting... v r

According to each'control unit is provided with two positivelymechanisms of small size and an improved ruggeds'tructure forestablishing the driving and locking connections required to acitua'tethe settable" element to'the desired settin precision accuracy,

and then stop the same "with "erm itting a wide range of adjust- =ment"of the settable element when actuated 'throughothers of the controluniti i It'is another objector-the invention to provide a lost-motiondevice wherein an improved 'speed. reducing mechanism em loying adinerential gear assembly having an exceedingly high drive ratio, isemployed totactuate. one of the relatively movable'lost motion parts. ofthe device, thereby to enhance the accuracy withwhich 'anothe'r of'the.parts is -.actuated after. the parts predetermined relative positions."

In accordancewith still. another object of the invention, an improvedcam and cam follower "assembly occupying a minimum'ot'spaceis utilizedto providethe 'required' lost motion in each 'device. p

It is a still furtherpbject of 'the invention to provide; an improvedmechanism for operating }a' controlled element with precision accuracyWhen an associated actuating" element is operated to a predetermine Settafurther object of the invention,

shaft' Ina of December is, 1943, Serial Ne.514,4e3 6 Claims. (01. 192-31) 2 as to its organization and W 7 together with further ob Scots andadvantages thereof, will best be under-,- st-oo-d by reference to thefollowing specification taken in connection with the accompanyingdrawings, in which: f :1

Fig. l'is a fragmentary plan view illustrating improved controlapparatus characterized by the features of the present invention;

' Fig. 2 is a fragmentary end viewpartially in section of the apparatusshownin Fig. 1;

. Fig. 3 is an edge sectional viewillustrating' the parts of one of thecontrol units providedin' the control apparatus shown in Fig. 1; i T

Fig. 4 is a side view of the control unit shown in'Fig. 3 withiiartsthereof broken away to show the driving relationship between certain ofthe elementsof the mechanism;

Fig. 5 'is an exploded perspective View of the parts making "up one-halfof thecontrol unit shown in Fig; 3;

The invention, both method of operation,

.Fig. 6 is a diagrammatic view illustrating the 'manne'r'in which therotary control'shaft of the control. apparatus may beactuated through adriving connection provided by the parts of one of thepontrol units; Y

Fig.7 is a circuit diagram illustrating the mannor of. electricallyenergizing the electromagnets and driving motor of the apparatus shownin Fi zlyand "1 i' 1' Fig. 8 is a sectional detailed view of'certain of,the parts includedinthe apparatus shown in i' F- 1 ,Referringnowto thedrawings, and more particularly to Figs. land 2 thereof,the improvedcontrol apparatusthere illustrated is adapted'to "a radio receivingsystem {or the ingthe frequency changing means '10 of thesystern-toidifferentipredetermined settings respectively corresponding todifferentdesired signal channels.- More'specifically,-the tuning orfrequencychanging' meanslfl of the receiver: is adapted to be actuatedto anyone ofa plurality of" different settings, respectivelycorresponding to different stations, by a single driving motor 13. Thismotor is arranged to rotate the settable vthe tuning means 10 throughanydriving connectionstwhich commonly include the gears 11 and 12,, a.rotary control' shaft" '15; an elongated driving gear 22, and the twomeshing motor driven gears Sand one of a plurality of 23: These :drivingconnections alsoindividually "include" control units 14 which areaxially disposedalong the rotary control shaft liand' are arranged to beselectively clutched to the elongated driving gear 22 by means ofclutching units 5'! individually associated therewith.

More specifically considered, all parts of the control apparatus aresupported between or upon two spaced-apart parallel extending framemembers I6 and I1. These members have suitable tie rods I 8 and atextendin therebetween and anchored thereto at the end portions thereoffor the purpose of enhancing the rigidity :of the structure. The motorI3 is mounted upon the frame member I! at the inner side thereof and isprovided with a rotor shaft 9a which extends through an opening in theframe member I1 and carries the driving gear 9. the drawings, theprojecting end of the shaft I311 is of reduced section and is formedwith a fiat I 3b near the outer extremity thereof. The shoulder portionI 30 of the shaft serves as a stop or abutment for a washer 8 of aclutch assembly I through which the shaft I3a and gear 9 are slipconnected. More specifically, this assembly comprises .a stresseddish-shaped sprin washer 5, the gear '9, a friction washe 4 and a collar3. The parts .of this assembly are maintained upon the shaft end, withthe washer 5 pressing the gear 9 against the friction washer 6, by meansof a set screw 2 which is threaded through the collar 3 to engage thefiat portion I30 of th shaft end.

The gear 23 which meshes with the driving gear 9 is preferably formed offiber or other like composition material, and is arranged to drive theelongated gear 22 through :a spring connection which includes the coilspring 26. More spe- .cifically, the gear 23 is rotatably supported by af retaining bushing '24 which is rigidly mounted upon the shaft end ofthe elongated gea 22. A steel washer 25 abutting against a shoulderedportion of the bushing 24 holds the gear 23 loosely upon the hub orbushing 24 so that it is free to rotate relative to the hub within thelimits imposed by the spring 26. One end of this spring is looped abouta friction screw 21 which holds the bushing 24 in a fixed position uponthe shaft end of the gear 22. The opposite end of the spring 26 ishooked into an aperture formed in the face of the gear 23. Thus, aflexible drive between the motor shaft I3a. and the elongated gear 22 isprovided which serves to prevent any possible locking of the clutchunits to the driving gear 22 in the manner more fully explained below.

As best shown in Fig. l of the drawings, the several control units I 4are arranged between the two frame members I6 and I! and each includesparts carried by three parallel extending shafts I5, 20 and 2|. The twshafts '20 and H are fixedly supported by the members I6 and I! at therespective ends thereof in the manner pointed out below. The third shaftI 5, as indicated above, constitutes the rotary control shaft andcarries stepped spacing sleeves 49 which are journaled in the framemembers I 6 and I 1 in an obvious'manner; This shaft has the gear I Iset screw mounted thereon at the end thereof which is adjacent thesettable element Iila of the tuning means II]. The several controlunits, which are axially disposed along the three shafts I5, *20 andY21, are of identical construction and arrangement. Accordingly,

the arrangementof these units will be readily understood from aconsideration of the control unit the parts of which are detailed inFigs. 3, .4

and -5 of the drawings.

In brief, this control unit comprises an actuating element 30 which ismounted for rotation with the rotary control shaft I5 and to whichrotation As clearly shown in Fig. 8 of may be imparted in differentdirections through two driving connections which respectively includethe driving elements 4| a and 4Ib and two combination speed reducing andlost-motion mechanisms. Each combination speed reducing and lost-motionmechanism comprises a pair of relatively movable pinion gears 32 and 33,the first of which is mounted for rotation with the shaft I5 and thesecond of which is rotatable relative to thisshaft and the :other g ar32an orbital or planetary gear 36 which is pivotally mounted by means ofan axis pin 31 upon the associated driving element 4| for meshingengagement with the associated gears 32 and 33; a camming element in theform of a ring 40 which is welded or pinned to the associated gear 33for rotation therewith about the shaft I5 and is provided around itsouter periphery with a cam lobe 42; a cam follower 38 which is pivotallysupported by means of a pin 43 at the outer periphery and to one side ofthe actuating element 30 for engagement by the associatedcam lobe 42when predetermined relative positions. of the two associated gears 32and 33 are established through operation of the associated drivingelement 4-I and a stop or projection 34 which is pinned by means of pins35 to the associated driving element II and is provided with aprojecting port-ion 44 adapted to be engaged by the associated camfollower 38 when this ;cam follower is actuated by the associated camlobe 42. Each gear 33 of the control unit is provided with -a differentnumber of teeth than the associated gear 32 so that during operation ofthe associated driving element 4I, it is rotated relative to theassociated driving element but at a much slower speed. For example, ifthe gear 33a is provided with sixty-one teeth and the gear 32a isprovided with sixty teeth, a 60:1 drive ratio is provided between thedriving element 4 la and the gear 3.3a, such that the latter element andthe cam ring a connected thereto are rotated one revolutionfor each.sixty revolutions of the driving element II a. Thus, the four elements4| a, 36a, 32a and 33a combine to form i an exceedingly compactdifferential gear assembly'through which the cam ring 40a may be rotatedat slow speed in response to high speed rotation of the driving elementa. The other differential mechanism of the control unit, i..e., thatcomprising the 'four elements Mb, 36!), 32b and 33b, is an exactduplicate of that described and utilizes the same drive ratio betweenthe driving elementi4Ib and the gear 331) thereof.

In' the assembly of the control unit l ia, two shouldered bushings 28aand 28b and two inner spacing rings 29a and 2% are utilized to providethe required bearing surfaces for those elements 4!, 33 and 43 which arerotatable relative to the control haft I5. The four identifiedsupporting members, together with the actuating element 33 and the twogears 32, are arranged in a stack, with the elements M, 33 and 40assembled thereon, in the manner just illustrated in Fig. 3 of thedrawings. Assembly pins 3| extending through the stack at severalpositions about the axis of the stack are utilized to provideclam-pingengagement between the parts 28, 29, 39 and 32, thereby tomaintain the enumerated parts of the control unit in their assembledrelationship. In

this regard, it is pointed out that each bearing ring 29 has a thicknesswhich is slightly greater than the combined thicknesses of the twoelements 33 and 40 which it supports, whereby these two elements arepermitted to rotate freely about the bearing ring 29 without'bindingengagement -the setting of the V semblyrcornprises a1 cammingmember 53 having In its engagement with and as'best shown..in-.FigI

withthe'adjacem elements and 32; Springs 39 are utilized to bias thelobes 46 of the cam followers 38 into engagement with the peripheralsurfaces of their respective associatedcamming elements 49. Morespecifically and as best shown in Fig. 5 of the drawings, thatperipheral portion of the actuating element 3|] which is disposedadjacent the free end of the camming element 38a'is cut away'to providea space within which the coilspring 39a; may be connected at oppositeends to the free end of the cam follower 38a and the actuating element30. This spring connection serves'at all times to bias the lobe 46a ofthe cam follower 38a into engagement with the outer peripheral surfaceof the camming ringlfla. 'An identical arrangement is utilized to biasthe lobe 46b of the cam follower 3811' into engagement with the outerperipheral surfaces of the camming ring b, it being noted in this regardthat the two cam followers are disposed upon opposite sides of theactuating element 30.

' From the above explanation it will be clearly apparent that eachcontrol unit is exceedingly compact in arrangement and is entirelyself-contained, such that it maybe removed from the rotary control-shaftl5 without disassembly of the'parts thereof. .As' best shown in Figs.land 3 of the'd rawings, bushings 48 are utilized fixedly to supporteach control unit l4 upon the rotary control shaft l5 and to maintainthe required axial spacing between each adjacent pair of controlunits."Morespecifically, the inner peripheral por'tion'of the'supporting stackof each control unitii's clamped between the oppositely arrangeshoulders of two shouldered bushings 48, these bushings being providedwith. inner flatted surfaces which are adapted .toengage the flat lea ofthe shaft l5 to provide a fixed. mechanical connection betweenthe shaftandthe control unit which the bushings support. At the ends of thecontrol shaft I5, the, stepped spacing sleeves 49 are provided, each ofwhich includes a'portion 49a of reduced diameteriwhich is journaledwithin'a opening provided in the adjacent one of the two framemembers l6and-l1; v Y g In order-frictionally to clamp the control units M betweenthe shouldered portions of the bushings 48 upon which they arerespectively sup ported spring washer assembly comprisingthe twobushings 5G and?! and the spring washer52,

and a clamping assemblyicomprising the three parts 53, and 56 areprovided. More specifically, the dish-shaped spring washer. 52 isdisposed between thetwo bushings 50 and 5 to-re tain a-slight clampingpressure againsttheas- I tionallyengageable with theirrespective'associated shafts by means of friction screwsf86. .Thethreaded ends-cf thetwo shafts 2B and-2| are held by nuts 88 to tieplates '81, and extend throughthefr'ame members l6 and 11, the nuts 88serving to hold the tie plates against the pinion assembly and to'spacethe pinions from the frame members it "and I'L Nuts 89 located upon theoutside of the" frame members 16 and I1 aregutilized; fixedly to mountthe shafts 253 and 2! thereon. a For the purpose of elongated gear 22 inselectively connecting the driving relationship with any onerof thecontrol units l4, clutching units 51 are provided individual to thecontrol units. Each clutching unit comprises an idler pinion B0pivotally supported by means of a pivot pin 6| upon an L-shaped rockerarm '62 whichis loosely mounted upon the shaft 2|; Each idler pinion 60is in meshing engagement with its associated pinion 58. At itsprojecting end, each rocker arm 62' carries an armature piece 63 whichis adapted to be attractedinto engagement withthe' projecting core end68 ofan electromagnet G'L-thereby to move the idler-pinion 6!! intomeshing engagement with the elongated drive gear 22 in response toenergization' of'this magnet. Inorder nor,- -ma1 ly tobias the rockerarm ,62 of each clutch assembly 51to a position wherein the idler pinion60' 'is disengaged'from the gear 22, each rocker arm is spring connectedthrough a coil spring 'to'thetie rod 65." Movement of the rocker arms62funder the influence of their respective associated-retracting springs65-is limited by the tie rod "18 which is positioned in the paths ofmovement of the rocker arms'and is provided with'a sernbly;stackofeach-control unit regardless of clamping. assembly. Thisascamming ides54 which engage a pin 55 extend ing through the shaft; 1 and is providedwith a cross bar which'is threaded to receive a screw.56. the shaft l5,this screw may be utilized to .move

ofthe shaft for the purpose of exerting an axial clamping pressure uponthe-parts '49, 48,: 50,15! 1 thefmember 53 radially and bi-Yin themanner morefully explained; V

below. Q'I'helgd ivin trol unit-J4 are vin meshing engagement withpinions fiaanclja respectively carried by the two shafts, -2l and 20.More specifically stationary .1 of the drawings the elements-Ha .andfdlbof each con- I H; and is anchored 'thereof.--This crossbar also supportsa terminal- The motor may'beso arrangedthat cushioning sleeve" it formedof rubber or other softi flexible material; The electromagnets- 61 are,all bolted to a crossbar-69 which extends transtwo frame members It;and to these members at the ends versely. between the strip T6 formed ofBakelite or other-suitable -insulating material having terminal elementssuitably mounted "thereon for connection with the wind- :ing terminalsof the electromagnets 61. ii 1 i3 is ofthe unidirectional :type and itsrotor is rotated in a counterclockwise direction as viewed in Fig, 6

gof the' drawings' With the driving gear 22 thus rotating ina clockwisedirection-theidler pinions areadapted for counterclockwise rotation whenengaged with thedriving pinion 22.1, Accordingly,

when any selected idlerpiniontfl is actuatedinto meshing engagementwiththe driving gear 22, the

meshing engagement of the geartn with its assopinionsr58 and5Sthrough'their meshing engagement withea'chother, are so arranged thatthey rotate the drivingelements Ala and; 4lb inopciated' pinion 58produces "pull the pinion tointomeshing engagement .with thedriving-gear 22,

ationg Since this-meshing. engagement h01ds;th e. armature p ece .63 initsattractedposition against properly a forcewhich acts to therebytOfilQCk the pinion I -'and-'driving gear in mesh during the tuning operthe magnet core 68, a mechanical pressure urging the armature piece 63toward the magnet core occurs concurrently with the electricalattraction of this piece by the core, whereby the magnet is aided inoperating the movable parts of the clutch assembly. The magnets 51,therefore, need only be large enough to attract their associatedarmature pieces into engagement with the magnet cores. This utilizationof the mechanical reaction between any one of the pinions 60 and itsengaged pinion 58 provides for the use of relatively small magnets 61,since each magnet merely functions to initially engage the idler pinionwith the driving gear; the pulling of the pinion into meshing engagementwith the gear being sufiicient to maintain the geared or interlockedengagement between the two elements so long as the driving gear isrotating. The coil spring 26 through which the gear 22 is driven by themotor 93 insures positive disengagement of the idler pinion 60 embodiedin any actuated clutch unit when the electromagnet 67 of the unit isdeenergized upon completion of a tuning operation.

For the purpose of energizing the motor I 3 and selectively controllingthe energization of the clutch magnets 5! individual to the severalcontrol units M. the control circuit illustrated in Fig. '7 of thedrawings may be employed. Briefly considered, this circuit comprises atransformer 75 having a primary winding a adapted to be connected to asuitable commercial frequency source of alternating current and asecondary winding T57) from which current is delivered for energizingthe motor l3 and selectively energizing the magnets 51. The transformer15 also includes a low voltage winding 50 for supplying cathode heatingcurrent to the heaters of the tubes provided in the radio receiverequipped with the illustrated control apparatus. Two additionalsecondary windings 15d and 15e are provided, which are included in theillustrated full wave rectifying circuit, this circuit being utilized tosupply the screen and anode potentials required for operation of thevarious tubes provided in the receiver. In order selectively to controlthe energization of the motor l3, the magnets 61, the cathode heatingcircuit, and the rectifying circuit, switching equipment is providedwhich includes off switch 8-3, push button switches 84 individual to thevarious magnets 61, and a relay switchin unit indicated generallyat 95.This unit includes two mechanically interlocked magnets 76 and 78, thesecond of which includes an armature l9 interlocked with the armature 11of the magnet 16 and arranged to control three sets of contacts 83, 8|and 82. The magnet 76, together with the armature and contact springassemblies thereof, are shown in Fig, 1 of the drawings as being mountedupon an assembly plate 96 which is rigidly secured to the frame memberIT.

In considering the operation of the control apparatus as describedabove, it may be assumed that this apparatus is to be utilized toactuate the tuning means I!) of the receiver to the particular settingcorresponding to the control unit Ma, thereby to tune the receiver forthe reception of signals radiated at the particular carrier fre quencyto which the control unit Ma corresponds. In order to initiate theoperation of this control unit, the push button switch 34a, associatedwith this control unit is actuated to its close-d circuit position,thereby to complete a circuit for energizing the clutch magnet 61individual to the control unit 14a in series with the driving motor I3and the winding of the magnet 16. When energized in this circuit, themagnet 16 attracts its associated latching armature 11, thereby torelease the spring biased armature 19 of the magnet 18. The armature 19in moving to its retracted position, closes the contacts to complete thecathode heater circuit, and at the contacts 8i and 82, completes thehigh voltage rectifying circuit in an obvious manner.

When the electromagnet 61 individual to the control unit Ma is thusenergized, the armature piece 63 of the clutch unit 51 associated withthis control unit is attracted, whereby the rocker arm 62 0f the clutchunit is pivoted about the shaft 2! against the bias of its retractingspring 65 to move the idler pinion 60 into engagement with the drivinggear 22. Thus, a driving connection is established between the motor 13and the driving elements 41a and 41b of the control unit Mo. As will beseen-from Fig. 6 of the drawings, when the motor I3 is energized in themanner just explained, it rotates the gear 9 in a counterclockwisedirection through the slip clutch connection provided between this gearand the motor shaft l3a. Accordingly, the gear 23 is actuated to rotatethe elongated drive gear 22 in a clockwise direction through'theresilient connection provided by the spring 26. As a result, the twopinions 58 and 59 are respectively rotated in clockwise andcounterclockwise directions through the driving connection afforded bythe idler pinion Ell in its engagement with the driving gear 22. Thus,driving connections are provided, whereby the driving element Ma isrotated in a counterclockwise direction and the driving element Mb in aclockwise direction relative to the rotary control shaft 15.

During rotation of the driving element lla, the planetary gear 360, isrotated about the two gears 32a, and 33a and, due to the toothdifferential between these two gears, the gear 33a and the cammingelement 46a connected thereto are rotated in the same direction as thedriving element Ma, i. e., in a counterclockwise direction about therotary control shaft IS. The driving element 4!]; similarl functions todrive the camming elements 481) in a clockwise direction relative to therotary control shaft l5 through the driving connection provided by thediiferential gears 32b, 33b and 36b. During such rotation of the twocamming elements 49a and 4% the actuating element 3!! for the rotarycontrol shaft l5 remains stationary until the cam lobe 42 carried by oneof the two cammin elements is positioned to actuate its associated camfollower 38 into engagement with the associated stop 34 carried by theassociated driving element 4 I. With the camming element 40b rotating inthe direction indicated, i. e., in a clockwise direction, the cam lobe42b thereof will engage one of the camming surfaces of the lobe 46b whenit is moved to the proper position relative to the actuating element 30.After such engagement, and during continued rotation of the cammingelement 4%, the two engaged lobes 42b and 45b coact to pivot the camfollower 38b in a counterclockwise direction about its pivot pin 43h sothat the stop engaging head 45b thereof is moved radially outward fromthe shaft I5. Approximately when the lower knife edge of the lobe 46b ismoved to bear against the upper knife edge of the lobe 426, the lockinghead 45b of the cam follower 38b is positioned to be engaged by theprojection 44b of the stop element 34b. The engaged surfaces the stop34a are cut at an of the two 'engagedelements 34b and 441 are cut on abias so that the continued; movement of the driving: element 4] b,following engagement of the two elements, provides a solid mechanicalinterlock therebetween. 1

In a manner entirely-similar tothatjust described, the camming element40a is rotated until the cam lobe 42a thereof is moved into engagementwith the lobe 46a of the--cam follower 38a. Here. again, when the twolobes 42a and 46a are relativelyso positioned that, when theirknifeedges are engaged, the head 45a of the cam follower 38a ispositioned for engagement by the projection Ma of the stop. element 34a.In this case also, the engaged edges of the head 45a and angle such thatthe two elements areinterlocked by continuedoperation of the drivingelement 4 lb.

From the above explanation it will be understood that when the camfollower 38a is engaged by the stop 34a, a direct mechanical connectionis provided between'the driving element Ma and theactuating element 30.When this connectionis established, rotation of the planetary gear 36aabout the two gears 32a and 33a is obviously arrested with the resultthat relative movement between the parts 30, 40a, 33a, 32a, 36a and Alais entirely discontinued. In a similarmanner, relative movement betweenthe parts Mb, 36b, 32b, 33b, 40b and 30 is arrested when the camfollower 38b is moved to a position for engagement by the stop 44bcarried by the driving element llb. a v I From the above explanation itwill be apparent that depending upon the initial setting of the controlunit Ma, the rotary control shaft 15 and the actuating element 30 willbe rotated in one direction or the other by one of the two drivingelements Ma or Mb. Thus, if the stop 34a engages the cam follower 38abefore the stop 34b engages the cam follower 381), the actuating element30 and control shaft l will be rotatedin a counterclockwise direction tothe predetermined setting to which the control unit [4a corif the stop34b is moved to responds. Conversely, v

38b before the stop 34a engage the cam follower engages the cam follower38a, the actuating element 30 and the control shaft 15 will berotated ina clockwise direction to the predetermined setting corresponding to thecontrol unit Ma. In either case, the actuating element 30 and the shaftl5 are rotated at the speed of the driving element 4| with which theyare mechanically connected until the nonengaged stop and cam followerare brought into engagement. When both of the two stop'elements 34a and341) are moved into engagement with the cam followers 38a and 3%,respectively, a locking connection is obviously established whichprevents continued rotation of the parts I5, 30, M, 58, 59, 60, 22, 23and 9. Thus, the entire gear train extending back to the motor drivinggear 9 is locked up when the shaft [5 is rotated to the predeterminedsetting corresponding to the actuated control unit Ma. After this trainhas been locked'up, continued rotation of the motor shaft He ispermitted through the slip clutch connection between this shaftandthe'gear 9. Y

When the new setting of the settable element Inc for the tuning'means I0is established in the manner just explaned, the operator will beapprised of this fact through reception of the'desired station and mayrelease thepush button switch 84a to deenergizethedriving motor 13,

the energized electromagnet 61 and the winding 1.0 of the magnet, 16 inan obvious manner. When the, magnet 16 is thus deenergized, its springbiased armature 11 is retracted to a position beneath the armature 19 ofthe magnet 18, but this operation is obviously without effect, and thepower circuits of the receiver remain energi'zed. When the electromagnet61 of the clutching. unit associated with ,theflcontrol unit I4a isdeenergized, its associated rocker arm 62 is spring actuated by theassociated spring 65 to its normal position wherein the idler pinion 60of the actuated clutching unit 51 is disengaged from the driving gear22. vIn this regard it is noted that upon deenergization of the drivingmotor 13, the coil spring 26 connected between the gear '23 and thedriving gear Z2'provides a kick-back action to insure release of theidler pinion 60. by .the driving gear 22. The manner in which theremaining control units l4 may, through selective energization of, themagnets 61 by the push button switches 84, be actuated for the purposeof driving the settable element we to its other predetermined settings,will be clearly apparent from the above explanation with reference totheoperation of the control unit Me. If at any time it is desired to turnoff the receiver after a period of operation, the off switch 83 may bemomentarily operated to its closed circuit position thereby to completean obvious circuit for energizing the winding of the, magnet 18. Thismagnet, in attracting its associated. armature 19, opens the contacts todeenergizethe cathode heaters of the tubes provided in the receiver. Atthe contacts 8| and 32, the magnet 18 opens the Bsupplycircuitsto thetubes and deenergizes the cathode heaters 0f the full waverectifyingtube provided; in the rectifying circuit. As the armature 19 is moved toits attracted position, the free end thereof rides over the lockingportion of the armature 11. After the switch .83 is released todeenergize the winding of the magnet 18, therefore, the armature .19 isheld in its attracted position by the latching armature 11 of the magnet16. During the above described movement of the shaft. [5 to theparticular setting corresponding to the control unit Ma, the movableparts of the nonactive control units are also moved to produceunlatching relative movement between the cam and cam follower parts ofone of the lost-motion mechanisms provided in each unit. In this regardit will be understood that as the control shaft 15 is rotated, all ofthe actuating elements 30 individual to the various control units arerotated therewith. The action which occurs in the nonactive units willbe more fully apparent from the following explanation relating to themovement of the parts provided in the control unit I la when the controlshaft 15 is driven to another predetermined setting by another of thecontrolunits. Thus-it may be assumed that after the rotary control shaft[5 is operated to the setting corresponding to the control unit I la,such that the cam followers 38a and 381) are respectively in engagementwith the stops 34a and 3%, the shaft I5 is rotated by a second controlunit in a clockwise direction. During such rotation of the shaft 15 thecam follower 38a remains in engagement with the stop 34a to preventrelative movement between the parts 41a, 36a, 32a, 33a, -40a and 30 ofthe control unit. Thus, the driving gear 41a which is rotating in 'aclockwise direction, is ren-. dered operative to drive the drivingelement 41b in a clockwise direction through the driving connectionafforded by the meshing pinions 58 and 59. The relative movement thusproduced between the driving element MI) and the actuating element 39 byrotating these two elements in opposite directions causes the stop 34band the cam follower 38b to be disengaged in a manner which will beclearly apparent from the following explanation.

Assuming now that the rotary control shaft I5 is rotated in acounterclockwise direction away from the predetermined settingcorresponding to the control unit Ma, the actuating element and drivingelement 41b of this unit are rotated in the same direction due to theengagement between the cam follower 38b and stop 34b respectivelycarried thereby. The gear 32a is also rotated in a counterclockwisedirection with the two elements 39 and 4| b. Also, and due to thedriving connection afforded by the pinions 59 and 58, the drivingelement lla is rotated in a clockwise direction relative to the shaftI5. With the two elements 4 la and 3211 thus rotating in oppositedirections and with the element lla rotating in a direction opposite thedirection of rotation of the actuating element 30, the planetary gear36a functions to rotate the gear 33a and camming element 49a in aclockwise direction relative to the actuating element at. Thus, the camlobe 42a is withdrawn from beneath the lobe 46a of the cam follower 33ato prevent reengagement of the stop 34a with the cam follower 38a afterthe two elements Ma and 30 have been relatively rotated through onerevolution. As relative movement between the two elements 4 Ia and 30continues, the cam lobe 42a is gradually backed away from the lobe 46auntil these two lobes are separated by a distance which is determined bythe amount, of movement required to actuate the shaft I 5 to its newsetting.

From the above explanation apparent that the rotary control settableelement moved to any desired setting through operation of a particularcontrol unit without any interference whatever from the nonactivecontrol units. This is due-to the fact that during operation of any oneof the control units to establish the de sired setting for the shaft I5,the parts of the nonactive units are so moved relative to each other as.to prevent a locking connection from beit will be clearly shaft I5 andthe ing established through any one of these units.'

Thus, the two combination speed reducing and lost-motion mechanisms asprovided in each control unit, permit the rotary control shaft I5 toaccurately and positively driven in either direction to any one of thepredetermined settings respectively corresponding to the several controlunits.

In order individually to adjust the various control units relative tothe rotary control shaft I5, thereby to provide for operation of thisshaft by the various control units to the desired predeterminedsettings, the screw 56 in the clamping mechanism is withdrawn until thecontrol units are freed for rotation relative to their respectiveassociated supporting bushings 48. The shaft I5 is then adjusted to adesired control position or setting by a suitable manual control knob(not shown) provided for manually actuating the settable element Illa ofthe frequency changing means I0. During such rotation of the shaft I5the spring washer 52 serves to maintain sufficient clamping pressureagainst the elements 28 of the respective control units to prevent theshaft from being moved relative to the control units, the movement ofthe rotary control shaft Illa actuated thereby may be' I said actuatingelement being taken up within each control unit in "a manner which willbe clearly apparent from the above explanation. While the shaft I5 isheld in the position to which it is adjusted, by manually gripping thecontrol knob of the manual actuating means, the switch 84 associatedwith the particular control unit which is to be utilized in operatingthe rotary control shaft to the manually established setting, isoperated to energize the driving motor I3. and to engage the idlerpinion 66. of the clutching unit individual to the control unit with thedriving gear 22. The motor I3 is thus rendered operative to drive themovable parts of the selected control unit until these parts arelockingly engaged in the manner explained above. During the finalportion of the operation of the selected control unit and moreparticularly after one of the cam followers 38 is engaged by itsassociated stop 34, all parts of the control unit are rotated relativeto the shaft I5 and the bushings 48 upon which the control unit issupported. Thus, the selected control unit is actuated to a positionrelative to the rotary control shaft I5, such that when the shaft andcontrol unit are subsequently looked together, the control unit canthereafter only operate the rotary control shaft to the particularsetting which it occupies when the locking operation is completed. Theabove described procedure may be repeated for each of the other controlunits I4, in order to establish the other predetermined settings desiredfor the rotary control shaft I5. During each setting operation, thecontrol units which are not being adjusted are maintained in adjustmentbecause of the fact that their frictional engagement with the bushings48 is suificient to maintain their established positions relative to theshaft I5. When all of the control units I4 have been adjusted, the screw56 may be tightened to frictionally look all of the control units I4 infixed positions relative to the shaft I 5, in a manner which will beclearly apparent from the foregoing explanation.

been disclosed, modifications may be made therein, which are within thetrue spirit and scope of the invention.

I claim:

1. In combination, a rotatable actuating element, a second elementmovable in a path extending radially of the axis of rotation of saidactuating element, lost-motion means operative to actuate said secondelement along said path, and a differential gear mechanism operated byand operative to take up the free travel in said lost-motion means andto then operate said second element through said lost-motion means.

2. In combination, a rotatable actuating element, a camming elementrotatable about the same axis as said actuating element, speed reducingmeans connecting said actuating element in driving relationship withsaid camming element, and an additional element actuated by said cammingelement when said camming element is operated to a predetermined angularposition.

3. In combination, a rotatable actuating element, a second elementmovable in a path extending radially of the axis of rotation of saidactuating element, a camming element operative to actuate said secondelement when moved into a predetermined position, and a speed reducinggear mechanism connecting said actuating means in driving relationshipwith said camming element.

4. In combination, a pair of relatively rotatable gears having differentnumbers of teeth, a rotatable actuating element, a planetary gearrotatably supported upon said actuating element for meshingengagementwith said pair of gears, whereby relative rotation actuating element torotate said planetary gear about said pair of gears, a controlledelement, and means responsive to the operation of said pair of gearsinto predetermined relative positions for actuating said controlledelement'from one position to a different position.

5. In combination, a pair of relatively rotatable gears having differentnumbers of teeth, a rotatable actuating element, a planetary gearrotatably supported upon said actuating element for meshing engagementwith said pair of gears, whereby relative rotation between said pair ofgears is produced in response to operation of said actuating element torotate said planetary gear about said pair of gears, a controlledelement,

between said pair of gears is produced in response to operation of saidgears is produced in response and means comprising a camming elementrotatable with one of said pair of gears for actuating said controlledelement from one position to a different position in response to theoperation of said pair of gears into predetermined relative positions.

6. In combination, a pair of relatively rotatable gears having differentnumbers of teeth, a rotatable actuating element, a planetary gearrotatably supported upon said actuating element for meshing engagementwith said pair of gears,

whereby relative rotation between said pair of tooperation of saidactuating element to rotate said planetary gear about said pair ofgears, said actuating element and pair of gears having a common axis, acontrolled element movable in a path extending radially of said axis,and means comprising a camming element rotatable with one of said pairof gears about said axis for moving said controlled element along saidpath in response to the operation of said pair of gears intopredetermined relative positions.

HAROLD F. ELLIOTT.

